In the present study an experiment investigating the possible effects of two types of form-focused instruction (FFI henceforth) on the acquisition of a specific feature of the Italian verbal morphology system (namely the future tense) will be described. Processing instruction was compared to an output-based type of grammar instruction. The impact of these two types of instruction was investigated on a well-documented strategy (Musumeci, 1989) used by second language (L2 henceforth) learners when interpreting tenses. This strategy consists in giving precedence to lexical items (in this case temporal adverbs, i.e. oggi, domani) over morphological markers during the learner’s interpretation of tenses. In this study, processing instruction involved grammar explanation and comprehension practice directed at altering the way second language learners process input and make correct meaning-form connections. The output-based instructional treatment consisted in the explanation of grammar rules followed by written and oral practice (part of which was meaning-oriented) which was directed at altering the way L2 learners produce the target language. Three tests were developed for this study and consisted of an aural interpretation task, a written completion text and an oral limited response production task. The results obtained in this research provide some evidence that processing instruction has positive effects on the acquisition of Italian verbal morphology, and greater effects on the developing system of beginner L2 learners than instruction of the output-based type described in this study. These effects were proved durable over a three-week period.